libavcodec/ac3_parser_internal.h

   1 /*
   2  * AC-3 parser internal code
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef AVCODEC_AC3_PARSER_INTERNAL_H
  22 #define AVCODEC_AC3_PARSER_INTERNAL_H
  23
  24 #include <stddef.h>
  25 #include <stdint.h>
  26
  27 #include "ac3defs.h"
  28 #include "get_bits.h"
  29
  30 /**
  31  * @struct AC3HeaderInfo
  32  * Coded AC-3 header values up to the lfeon element, plus derived values.
  33  */
  34 typedef struct AC3HeaderInfo {
  35     /** @name Coded elements
  36      * @{
  37      */
  38     uint16_t sync_word;
  39     uint16_t crc1;
  40     uint8_t sr_code;
  41     uint8_t bitstream_id;
  42     uint8_t bitstream_mode;
  43     uint8_t channel_mode;
  44     uint8_t lfe_on;
  45     uint8_t frame_type;
  46     int substreamid;                        ///< substream identification
  47     int center_mix_level;                   ///< Center mix level index
  48     int surround_mix_level;                 ///< Surround mix level index
  49     uint16_t channel_map;
  50     int num_blocks;                         ///< number of audio blocks
  51     int dolby_surround_mode;
  52     /** @} */
  53
  54     /** @name Derived values
  55      * @{
  56      */
  57     uint8_t sr_shift;
  58     uint16_t sample_rate;
  59     uint32_t bit_rate;
  60     uint8_t channels;
  61     uint16_t frame_size;
  62     uint64_t channel_layout;
  63     int8_t ac3_bit_rate_code;
  64     /** @} */
  65 } AC3HeaderInfo;
  66
  67 /**
  68  * Parse AC-3 frame header.
  69  * Parse the header up to the lfeon element, which is the first 52 or 54 bits
  70  * depending on the audio coding mode.
  71  * @param[in]  gbc BitContext containing the first 54 bits of the frame.
  72  * @param[out] hdr Pointer to struct where header info is written.
  73  * @return Returns 0 on success, -1 if there is a sync word mismatch,
  74  * -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate)
  75  * element is invalid, or -4 if the frmsizecod (bit rate) element is invalid.
  76  */
  77 int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);
  78
  79 int avpriv_ac3_parse_header(AC3HeaderInfo **hdr, const uint8_t *buf,
  80                             size_t size);
  81
  82 #endif /* AVCODEC_AC3_PARSER_INTERNAL_H */